Materials Data on Fe7Mo6 by Materials Project
Fe7Mo6 is Frank-Kasper $\mu$ Phase structured and crystallizes in the trigonal R-3m space group. The structure is three-dimensional. there are three inequivalent Mo sites. In the first Mo site, Mo is bonded in a 6-coordinate geometry to four Mo and twelve Fe atoms. There are one shorter (2.66 Å) and three longer (2.83 Å) Mo–Mo bond lengths. There are a spread of Mo–Fe bond distances ranging from 2.66–2.87 Å. In the second Mo site, Mo is bonded in a 6-coordinate geometry to nine Mo and six equivalent Fe atoms. There are a spread of Mo–Mo bond distances ranging from 2.75–3.03 Å. There are three shorter (2.68 Å) and three longer (2.71 Å) Mo–Fe bond lengths. In the third Mo site, Mo is bonded in a 8-coordinate geometry to eight Mo and six equivalent Fe atoms. The Mo–Mo bond length is 2.52 Å. All Mo–Fe bond lengths are 2.60 Å. There are two inequivalent Fe sites. In the first Fe site, Fe is bonded to seven Mo and five Fe atoms to form a mixture of edge, face, and corner-sharing FeFe5Mo7 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.37–2.39 Å. In the second Fe site, Fe is bonded to six equivalent Mo and six equivalent Fe atoms to form FeFe6Mo6 cuboctahedra that share corners with twelve equivalent FeFe5Mo7 cuboctahedra, edges with six equivalent FeFe6Mo6 cuboctahedra, and faces with eighteen equivalent FeFe5Mo7 cuboctahedra.